Standard feedback software can present additional challenges when the monitored function does not always behave in the expected or easily-interpreted ways. For example, in standard biofeedback on a day-to-day basis skin conductance behaves differently. It might change in very small amounts on a cold day, or experience large swings on a humid day. Likewise, participants with developmental differences manifest physiological differences that can reduce their benefit from standard feedback.
Prior technology allows for multiple signals to be displayed at the same time, though typically as disconnected pieces. Signals are also generally displayed in their standard units of measurement, making it more difficult to realize the way that changes match up across the different signals. This can quickly become confusing to new users since some variables will indicate success by decreasing while others will indicate success by increasing.